Worms and Trojan Horses

Whenever viruses are discussed, both Trojan Horses and Worms are discussed in the same context. A Worm is a program that duplicates itself without attaching its code to other programs. Worms normally exist on networks rather than single machines. A Worm creates a number of copies of itself, all running simultaneously, and thus slowing down the system. An example of a Worm is the US Internet Worm, which was injected into the Internet network. This program multiplied uncontrollably, eating up the available memory space of all the infected computers on the network until they could no longer function.

Bulletin boards on networks are the most common source of viruses. In a network, most users wishing to share software, place such software in a place called the bulletin board along with messages for other users. Sometimes virus programmers place infected programs onto the bulletin board and, as a result, the network gets infected. Network users should only access bulletin boards, but not download software from them to their workstations without checking the software for infection.

A Trojan Horse is a supposedly useful program, which encourages you to run it. But its real purpose is to damage files on your system, or to plant a virus or a worm. An example of a Trojan horse is Egabtr, (pronounced as eggbeater). Egabtr is an acronym for enhanced graphics adaptor beater. It is supposed to enhance the images on your screen, but it actually destroys data and programs on disks.

Another Trojan Horse called Stars, is a program to display visual effects on the screen. It does that but, at the same time, locates files containing the network users' passwords and destroys them.

Note: The anti-virus programs for Win NT are different from those for the Windows95 machines. These programs differ in construction as well as usage.